feat: create FormClosedPage and close provider form

src/pages/form_closed_page.rs

@@ -0,0 +1,20 @@
+use leptos::prelude::*;
+use crate::components::Banner;
+
+#[component]
+pub fn FormClosedPage() -> impl IntoView {
+    // This page simply shows a message saying a form is closed. It does not make any distinction
+    // about which form is closed right now.
+
+    view! {
+        <Banner
+            title="R15 Scholarships"
+            logo="/PHS_Stacked_Acronym.png"
+            path="/providers"
+        />
+        <div class="flex flex-1 flex-col gap-4 items-center m-4">
+            <div class="font-bold text-3xl">"This form has been closed!"</div>
+            <div class="text-lg">"If you believe this is an error, please contact Sara Smith at "<a href="mailto:ssmith@region15.org">"ssmith@region15.org"</a></div>
+        </div>
+    }
+}